# Change Trigger ### Change Trigger Change trigger specifies what changes the tag should notify all "interested" consumers about (OPC UA variable, time series, etc.). The following values are available: * **StatusValue** ensures the best performance, because in this mode the notifications are only sent after a change of status (for example, when the connection is lost) or value. * **StatusValueTimestamp** is the most resource-intensive notification mode. In this mode, the tag will signal its change with the frequency specified in the *Update Rate*, regardless of whether the status or value of the tag has changed or not. Change trigger affects the amount of data saved in the store if the tag is associated to a time series, as well as the filtering mode for OPC UA subscription. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.monokot.io/tags-and-devices/tags/change-trigger.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.